phnL is part of an operon that is phosphate starvation-inducible and required for use of phosphonate and phosphite as phosphorous sources [Yakovleva98, Metcalf91, Chen90a]. PhnL appears to be required for carbon-phosphorous lyase activity [Metcalf93]. A phnL mutant accumulates presumed intermediates of the C-P lyase pathway of phosphonate degradation [HoveJensen10].